L5 - evolution & genetics Flashcards
nature
genes determine behaviour
nurture
environment determine behaviour
interactionism
certain basic abilities innate but influenced by experience, which changes which innate behaviours are expressed, which in turn influences experience
interplay between genes & environmental factors
Piaget’s theory of human development: knowledge-compatable expriences assimilate, disequilibrium -> accommodation by changing concepts of world
nativism
knowledge of the world is innate/a priori (Descartes)
empiricism
mind at birth is tabula rasa, no knowledge/behaviour is inherited, all is learned (Locke)
proximate causation
internal change, explain how
ultimate causation
evolutionary change, explains why
genes do not cause behaviour, they allow certain behaviours to emmerge
species
tend to mate
produce fertile offspring
sapiens = wise
genus
species evolved from common ancestor
Homo = human
homo erectus
possibly also mated with H. sapiens
homo neanderthalensis
mitochondrial DNA found in Europeans & Asians
homo sapiens
outcompeted all other human species
walking upright -> see predators from afar & frees hands
out of Africa hypothesis
most widely accepted
modern humans evolved as one species in Horn of Africa 200-300k years ago before migrating out
most recent wave 50-70k years ago
multiregional hypothesis
evolution within single, continuous human species encompassing all human forms, evolved worldwide to diverse populations of modern humans
now more similar to assimilation model
cognitive revolution
70k years ago
greater ability to process information likely reason we outcompeted others
increase in brain size -> planning, coordination, communication, innovation
rapid behaviour change, more variety in tools & art
argricultural revolution
12k years ago
change from hunter-gatherer to domestication
population no longer restricted by food availability (security, feed more children)
more restrictive diet
many diseases (cavities, diabetes, cancer, zoonotic)
ownership
more dependent on weather
sedentary, more time working
trapped, no way back to old lifestyle
scientific revolution
500 years ago
Galileo, Bacon, Descartes
scientific method to understand & control nature
anthropocene
proposed new epoch charcaterised by human modification of entire biosphere, climate, geology, ecosystems
gene
DNA sequence
genotype
complete set of organism’s genes
phenotype
overt (observable) characteristics, produced by genotype & environment
epigenetics
regulation of gene expression
histones need to unwrap to allow access to DNA
chromosome
spool of genetic material wound around histones
diploid set
46 chromosomes
gene from both set codes for same thing, physicality dependent on gene expression
haploid set
23 chromosomes (egg & sperm)
allele
different form of same gene
homozygous
alleles code for same phenotype
heterozygous
alleles code for different phenotype, usually dominant gene is expressed
innate human behaviours
inborn abilities present at birth/rapidly during development
reflexes, attraction to novelty, play, manipulate objects, basic cognitive skills (counting), Moro reflex (falling), feeding
baby scheme/Kindchenschema
“cute” facial characteristics elicit caretaking behaviour
large head, round face, high protruding forehead, large eyes, smal nose & mouth
piloerection
hair stands up in reaction to fright & cold
makes us look bigger->scarier
insulation, keeps layer of air around skin
preference for cover
unconscious use of environmental features
remnant from being middle of food chain
children building forts, caves, hideaways
preference to sit with back against wall, take seats at corner & edge, high lookout for dwellings
innate social behaviours
shared with primates
stretching out hand as initiation of contact
body contact to signal affection
pet/carress from allogrooming
hard-wired facial expressions, re-enaction -> empathy
grasping reflex
newborns able to support own weight from climates clinging to mother’s fur
crying
reflex to sooth distressed child due to extreme unease (caring response, activates amygdala)
complex, well-coordinated, highly effective
twin studies on intelligence
comparing mono- & dizygotic twins in same vs dif environment
results: mostly genetic (twins always higher similarity in intelligence than siblings of unrelated) but somewhat influenced by environment
heritability
IQ scores of adopted children correlate more with biological relatives
heritability estimate for intelligence -.4-0.5 for children, 0.6-0.8 for adults
dizygotic twins
fraternal, from two different embryos (share half of genes)
monozygotic twins
identical, from same embryo
Darwin’s theory of evolution
factors: rapid multiplication, limited resources, competition (struggle for existence), more variation = more likely to adapt, survival of the fittest = natural selection acting on phenotype
random mutation -> not all offspring viable/will survive
prokaryotic cell
no membrane-bound organelles or nucleus
eukaryotic cell
plants, animals, contain specialised organelles
symbiotic process
not always competition/random mutation/natural selection, cooperative
complex eukaryotic cells emmerged from phagocytosis of other bacteria which became specialised organelles
endocymbiotic theory/theory of symbiogenesis
evidence:
cell cannot make organelles
double membrane
certain lipids in inner membrane
reproduce through binary fission like bacteria
circular ring DNA in mitochondria
consequences of cognitive evolution
birth canal limits brain size -> folded structure ARHGAP11A gene random mutation to B
2.5% weight, 25% energy vs apes 8%
compromise for brain energy consumption: muscle atrophy, weaker jaws
diet: cooking increases caloric density and digestion speed
premature births -> babies plastic, helpless for a long time, require group raising -> social by necessity -> language, possibly friendliness
consequences of language
coordination, planning complex actions
additive transmission of knowledge
abstract concepts, sharing myths, laws
friendliness, cooperation of strangers
larger societies (150 kinship tribes -> cities,nations)
problems with evolutionary psychology
modularity (discrete codeable modules, eg snake detection) - behaviour actually from complex interation of brain regions
confirmatory testing - little research based on experimentation, can only confirm not reject hypothesis
Simple genetic model - assumption that every trait must be genetic & increase fitness, but many in fact cultural (see mate selection)
